I found lots of really good options, but pyTenjin just jumped to my attention. It keeps things simple and fast, resulting on a single file library with a tool script to help template development. It works by generating python code from the templates. Pretty straightforward!
The tool script has lots of features like syntax checking, rendering html, using python code as context to setup data for the templates, and dumping the resultant python code for a given template. It was really easy to our Web Designer, Marcus Sousa, to start creating complex templates.
However, at some point I noticed that was cumbersome editing the template files, rendering it to a temporary html file and then see how it looks with the browser. So to eliminate this awkward roundtrip, my fellow coder Vitor Mazzi and I decided to build a Tenjin Server. A webserver written in python to serve templates, reducing Marcus working process to a matter of saving files and refreshing his browser.
The project is available at http://github.com/henriquebastos/tenjinserver. Feel free to clone it and improve as you wish.